CN113825571A - Organic solvent dispersions of hydrolyzable polymers - Google Patents
Organic solvent dispersions of hydrolyzable polymers Download PDFInfo
- Publication number
- CN113825571A CN113825571A CN202080036301.3A CN202080036301A CN113825571A CN 113825571 A CN113825571 A CN 113825571A CN 202080036301 A CN202080036301 A CN 202080036301A CN 113825571 A CN113825571 A CN 113825571A
- Authority
- CN
- China
- Prior art keywords
- organic solvent
- water
- hydrolyzable
- polymer dispersion
- polymer
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/04—Polyesters derived from hydroxycarboxylic acids, e.g. lactones
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/002—Reclamation of contaminated soil involving in-situ ground water treatment
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F3/00—Biological treatment of water, waste water, or sewage
- C02F3/28—Anaerobic digestion processes
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L67/00—Compositions of polyesters obtained by reactions forming a carboxylic ester link in the main chain; Compositions of derivatives of such polymers
- C08L67/02—Polyesters derived from dicarboxylic acids and dihydroxy compounds
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C1/00—Reclamation of contaminated soil
- B09C1/10—Reclamation of contaminated soil microbiologically, biologically or by using enzymes
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B09—DISPOSAL OF SOLID WASTE; RECLAMATION OF CONTAMINATED SOIL
- B09C—RECLAMATION OF CONTAMINATED SOIL
- B09C2101/00—In situ
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/163—Nitrates
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/10—Inorganic compounds
- C02F2101/16—Nitrogen compounds, e.g. ammonia
- C02F2101/166—Nitrites
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2101/00—Nature of the contaminant
- C02F2101/30—Organic compounds
- C02F2101/36—Organic compounds containing halogen
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2103/00—Nature of the water, waste water, sewage or sludge to be treated
- C02F2103/06—Contaminated groundwater or leachate
-
- C—CHEMISTRY; METALLURGY
- C02—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F—TREATMENT OF WATER, WASTE WATER, SEWAGE, OR SLUDGE
- C02F2305/00—Use of specific compounds during water treatment
- C02F2305/06—Nutrients for stimulating the growth of microorganisms
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L101/00—Compositions of unspecified macromolecular compounds
- C08L101/16—Compositions of unspecified macromolecular compounds the macromolecular compounds being biodegradable
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2201/00—Properties
- C08L2201/56—Non-aqueous solutions or dispersions
-
- C—CHEMISTRY; METALLURGY
- C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
- C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
- C08L2205/00—Polymer mixtures characterised by other features
- C08L2205/02—Polymer mixtures characterised by other features containing two or more polymers of the same C08L -group
Landscapes
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Organic Chemistry (AREA)
- Hydrology & Water Resources (AREA)
- Water Supply & Treatment (AREA)
- Environmental & Geological Engineering (AREA)
- Microbiology (AREA)
- Polymers & Plastics (AREA)
- Health & Medical Sciences (AREA)
- Medicinal Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Biodiversity & Conservation Biology (AREA)
- Soil Sciences (AREA)
- Processing Of Solid Wastes (AREA)
- Biological Depolymerization Polymers (AREA)
- Treatment Of Biological Wastes In General (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
A large-capacity organic solvent polymer dispersion comprising a nonvolatile water-soluble organic solvent and a hydrolyzable polymer dispersed therein, which maintains a water content of 1 mass% or less and has a drop time at 50 ℃ of 120 seconds or less as measured with a Zahn cup having an opening diameter of 5mm or less.
Description
Technical Field
The present invention relates to an organic solvent dispersion of a hydrolyzable polymer. More specifically, the present invention relates to an organic solvent dispersion of a hydrolyzable polymer which is consumed in large amounts by being thrown into the ground for use. In particular, the invention also relates to a purification agent suitable for purification of contaminated groundwater.
Background
Many measures have been considered and implemented against groundwater pollution caused by chemicals, some of which are regulated according to environmental standards and the like. Among them, in-situ purification, which is a technique for in-situ purifying contaminated groundwater without making a significant change to the present situation, is particularly useful.
In situ decontamination is known as a method of decomposing harmful substances using microorganisms (bioremediation). The method purifies harmful chemicals in groundwater by effectively using microorganisms existing in-situ soil where contamination occurs.
Meanwhile, among harmful chemicals, volatile organic chlorine compounds (hereinafter, referred to as "VOCs") such as tetrachloroethylene and trichloroethylene are managed according to environmental quality standards for groundwater pollution, and the demand for techniques for purifying these substances is high. Further, nitrate nitrogen and nitrite nitrogen (hereinafter, may be referred to as "nitrate/nitrite nitrogen") are also managed according to environmental quality standards for groundwater pollution, and techniques for purifying these substances are required.
Known techniques for purifying groundwater contaminated with VOCs and nitrate/nitrite nitrogen use anaerobic microorganisms. The technology purifies VOCs and nitrate/nitrite nitrogen by making the groundwater environment anaerobic and providing a hydrogen donor as an energy source for anaerobic microorganisms to decompose the VOCs and nitrate/nitrite nitrogen.
For example, when a water-soluble organic compound is injected into the ground as an energy source for anaerobic microorganisms, the aerobic microorganisms consume oxygen, thereby creating an anaerobic environment. As a result, the anaerobic microorganisms are activated, and thus the VOCs and nitrate/nitrite nitrogen are purified. Here, the water-soluble organic compound means a substance used as a nutrient source or a hydrogen donor for activating aerobic and anaerobic microorganisms.
In a ground where the groundwater flow speed is fast, the water-soluble organic compound is dissolved in water and easily flows out. This requires injecting a water-soluble organic compound outside the forehead where cleansing is completed, which requires time, effort, and money. In addition, even if the concentration of VOCs is reduced, VOCs contained in the surrounding soil may be dissolved out, thereby causing pollution again. In such cases, if the water-soluble organic compounds disappear, a sufficient anaerobic environment necessary for purification cannot be maintained, which makes it difficult for anaerobic microorganisms to purify VOCs, resulting in the re-occurrence (rebound) of groundwater contamination. Therefore, means for preventing groundwater contamination from occurring again at a place where contamination is likely to occur or a place where purification has been completed is required.
Various methods of using anaerobic microorganisms to purify VOCs and nitrate/nitrite nitrogen have been disclosed.
For example, patent document 1 discloses a method for in situ purification of contaminated soil and/or contaminated groundwater. In the method, a depurative having a melting point of 10 to 40 ℃ is heated to be melted, injected into contaminated soil or groundwater under pressure to be diffused therein, and solidified, thereby allowing microorganisms to proliferate under anaerobic conditions to effect decomposition.
According to the in-situ purification method described in patent document 1, the purifying agent solidified in the soil allows the anaerobic environment to be continued, and seems to prevent the reoccurrence of groundwater contamination. However, when the temperature of the application environment is low, the scavenger rapidly cools down and solidifies. As a result, the depurative injected through the injection well spreads over a small area, and therefore, only a limited area in the soil can be decontaminated.
In the method described in patent document 1, an organic compound (purifying agent) used as a nutrient source for anaerobic microorganisms is in a solid powder form when injected into the ground. The method can maintain the anaerobic environment for a long time, is suitable for ground with high permeability, and is effective for inhibiting rebound after purification. In particular, in the case where a high molecular weight resin is used as a depurative, the form is less likely to collapse even in soil, and gradually decomposes with the passage of time. As a result, the anaerobic environment can be continued for a longer period of time.
In carrying out the above method, the solid powdered decontaminant to be injected preferably has a smaller particle shape so that it can be injected into a wider area of the ground. Meanwhile, the organic compound processed into a fine powder has a larger surface area and thus is easily aggregated. Therefore, it is difficult to uniformly disperse in water as a medium. In particular, when a solid powdery resin is used, such resin is not generally dispersed in water only by addition to water, but is unevenly aggregated or floats on the water surface, resulting in a significant decrease in handling.
Therefore, there is room for improvement in the form of the purification agent used.
In order to improve the above problem, the present applicant and others have proposed a method for purifying contaminated groundwater in patent document 2. The method uses a water-soluble organic compound and a particulate hydrolyzable resin in combination as a hydrogen donor. The hydrolyzable resin particles are added to a water-soluble organic compound and stirred, and then mixed with water, thereby preparing a mixed solution. The mixed solution thus obtained was poured into soil.
According to this method, a water-hydrolyzable resin powder such as polylactic acid or polyoxalate is mixed with a water-soluble organic compound such as a carboxylic acid salt such as sodium lactate or a carboxylic acid such as lactic acid to form a paste. At the time of purification, the paste is mixed with water and poured into soil. The hydrolyzable resin particles are hydrolyzed in the soil to serve as a hydrogen donor. Thereby, the anaerobic environment can be maintained for a long period of time even in a ground with high permeability. Further, the use of the water-soluble organic compound makes the hydrolyzable resin easily dispersible in water, ensuring operability. In addition, the water-soluble organic compound also serves as a hydrogen donor, which allows an anaerobic environment to be formed even in a state where the hydrolyzable resin particles are not hydrolyzed. As a result, it becomes possible to maintain the anaerobic environment for a longer period of time and effectively suppress the rebound after purification.
However, the greatest disadvantage of the method of patent document 2 is that the industrial feasibility is poor, and this problem is not considered in patent document 2.
More specifically, the paste of the hydrolyzable resin particles and the water-soluble organic compound has very high viscosity and is difficult to produce in a large mixing tank for industrial use. For example, in the case of small-volume production for laboratory use, mixing in a mortar as employed in the example of patent document 2 is applicable. However, in the case of producing a decontamination preventing agent for supplying contaminated groundwater to the ground, the above-mentioned mixing means cannot be employed because the amount of the decontamination agent consumed for such use is large. Mixing using a large capacity mixing tank is indispensable for industrial feasibility. However, in the case of mixing using a large-capacity mixing tank, it is difficult to take out the paste from the mixing tank, and a large amount of the paste adheres to and remains on the wall surface of the mixing tank, resulting in a very low yield. To prevent adhesion to the walls of the mixing tank, water may be added for viscosity control. However, the addition of water allows the hydrolysis of the hydrolyzable resin to proceed rapidly after paste control. As a result, most of the hydrolyzable polymer is hydrolyzed before actually being injected into the ground. Therefore, it becomes impossible to maintain an anaerobic environment in a soil with high permeability for a long period of time.
Prior art documents:
patent documents:
patent document 1: JP 3694294B 2
Patent document 2: JP 2018-143918A
Disclosure of Invention
Problems to be solved by the invention
Accordingly, it is an object of the present invention to provide a large volume of consumed organic solvent polymer dispersion suitable for use as a purification agent for purifying contaminated groundwater.
It is another object of the present invention to provide a large-capacity organic solvent polymer dispersion particularly suitable for use as a depurative supplied into the ground to purify contaminated groundwater.
Means for solving the problems
The present invention provides a large-capacity organic solvent polymer dispersion prepared by dispersing a hydrolyzable polymer in a nonvolatile water-soluble organic solvent, which maintains a water content of 1 mass% or less and has a drop time at 50 ℃ of 120 seconds or less as measured by a Zahn cup having an opening diameter of 5mm or less.
Further, the present invention provides a method for using the large-capacity organic solvent polymer dispersion, which comprises supplying the large-capacity organic solvent polymer dispersion into the ground.
In the high volume organic solvent polymer dispersion of the present invention, the following embodiments are preferred:
(1) the large-capacity organic solvent polymer dispersion has a capacity of 1,000L or more;
(2) the water-soluble organic solvent is polyhydric alcohol;
(3) the hydrolytic polymer is aliphatic polyester;
(4) the aliphatic polyester is polylactic acid or polyoxalate;
(5) the retention rate of the weight average molecular weight of the hydrolyzable polymer when left at 50 ℃ for 30 days is maintained at 80% or more; and
(6) large volumes of organic solvent polymer dispersions are fed into the ground to purify contaminated groundwater.
ADVANTAGEOUS EFFECTS OF INVENTION
The large-capacity organic solvent polymer dispersion of the present invention is prepared by dispersing a hydrolyzable polymer in a water-soluble organic solvent, maintains a water content of 30 mass% or less, and has a drop time at 50 ℃ of 120 seconds or less as measured by a Zahn cup having an opening diameter of 5mm or less. That is, even when the organic solvent polymer dispersion is produced in a large capacity (for example, 1,000L or more) by an industrial mixing tank, it can be easily taken out from the mixing tank, and is effectively prevented from adhering to and remaining on the wall surface of the mixing tank, resulting in a high yield. Thus, the high capacity organic solvent polymer dispersions of the present invention are useful for high volume consumer applications.
Further, according to the large-capacity organic solvent polymer dispersion of the present invention, the hydrolysate of the hydrolyzable polymer and the water-soluble organic solvent function as a hydrogen donor serving as a nutrient source for the anaerobic microorganisms, thereby contributing to the formation of an anaerobic environment. As a result, groundwater contaminated with volatile organic chlorine compounds (VOCs), nitrate nitrogen, nitrite nitrogen, and the like can be purified.
Furthermore, the dispersions of the present invention contain an extremely limited amount of water, and the water-soluble organic solvent itself is clearly less likely to hydrolyze the hydrolyzable polymer. Thus, the hydrolysis of the hydrolyzable polymer is effectively prevented before the dispersion is injected into the ground, for example, when stored or transported or the like. Therefore, when the hydrolyzable polymer is injected into the ground, it is not carried by flowing water or consumed in a short time as a nutrient source for microorganisms, but is hydrolyzed over time to be consumed as a nutrient source for microorganisms. In addition, the water-soluble organic solvent serves as a nutrient source for microorganisms before the hydrolysate of the hydrolyzable polymer is formed. Thereby, the underground environment can be kept anaerobic for a long period of time, and thus it becomes possible to purify the contaminated groundwater and effectively prevent the reoccurrence of groundwater contamination.
In addition, the large-capacity organic solvent polymer dispersion is suitable for being consumed in large amounts by being supplied into the ground, and the polymer dispersed therein exhibits moderate hydrolyzability. Thus, the dispersion may also be suitable for use in the preparation of fracturing fluids (aqueous wellbore dispersions), for example for the recovery of subterranean resources such as shale gas.
Detailed Description
The large-capacity organic solvent polymer dispersion of the present invention is prepared by dispersing a hydrolyzable polymer in a water-soluble organic solvent so that the hydrolyzate of the hydrolyzable polymer and the organic solvent contribute to the formation of an anaerobic environment in the ground. In addition, when the present invention is applied to the preparation of fracturing fluids, the hydrolysable polymer acts as a filler to temporarily close the fractures on the well.
A hydrolyzable polymer:
the hydrolyzable polymer used in the present invention is a water-insoluble resin that is hydrolyzed to a low molecular weight monomer in the presence of water. For example, an aqueous dispersion containing the resin at a concentration of 5mg/ml is prepared and left to stand at 25 ℃. After several days, 20mL of the dispersion was taken out and filtered through a 0.45 μm filter. The amount of Total Organic Carbon (TOC) measured by a total organic carbon meter (TOC meter) is 0.5 ppm/day or more for 30 days or more. Such a hydrolyzable polymer can be injected into a soil having a large permeability even without being carried by flowing water, and gradually hydrolyzed in the soil to generate a hydrolysate serving as a hydrogen donor to function as a nutrient source for aerobic microorganisms. Thus, the aerobic microorganisms are activated, making the underground environment an anaerobic environment. As a result, the anaerobic microorganisms are activated to decompose pollutants such as volatile organic chlorine compounds (VOCs), nitrate nitrogen, and nitrite nitrogen. In addition, the hydrogen donor, i.e., the hydrolysate, also has the property of decomposing the VOCs by reacting with and capturing the chlorine atoms that the VOCs have.
Representative examples of the hydrolyzable polymer as described above include hydrolyzable resins such as polyester and polyamide, polysaccharides, proteins, although the present invention is not limited thereto.
Polyesters are essentially polycondensation products of polycarboxylic acids and polyols.
Representative examples of polycarboxylic acids include dicarboxylic acids such as oxalic acid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, and cyclohexanedicarboxylic acid.
Examples of polyols include ethylene glycol, propylene glycol, butylene glycol, octanediol, dodecanediol, neopentyl glycol, glycerol, pentaerythritol, sorbitan, bisphenol a, and polyethylene glycol.
The polyester can be obtained by polycondensation of hydroxycarboxylic acid or ring-opening polymerization of lactone, or the like.
Examples of hydroxycarboxylic acids include glycolic acid, lactic acid, malic acid, hydroxypropionic acid, hydroxybutyric acid, hydroxyvaleric acid, hydroxycaproic acid, and hydroxybenzoic acid. Examples of lactones include glycolide, caprolactone, butyrolactone, valerolactone, propiolactone, and undecalactone.
Polyamides are polycondensation products of polycarboxylic acids and polyamines or are obtained by ring-opening polymerization of lactams.
Representative examples of polycarboxylic acids include dicarboxylic acids such as succinic acid, adipic acid, sebacic acid, glutaric acid, sebacic acid, cyclohexane dicarboxylic acid, terephthalic acid, isophthalic acid, and anthracene dicarboxylic acid.
Examples of the polyamine include diamines such as hexamethylenediamine, nonanediamine, methylpentanediamine, and phenylenediamine.
Examples of lactams include caprolactam, undecanolactam, and laurolactam.
Examples of polysaccharides and proteins include starch, modified starch, cellulose, chitin, chitosan, gluten, gelatin, soy protein, collagen, and keratin.
In the present invention, each of the above hydrolyzable polymers may be used alone or in combination with one or more other hydrolyzable polymers.
Among the above-mentioned hydrolyzable polymers, aliphatic polyesters are preferable from the viewpoint of moderate hydrolyzability. For example, poly (. alpha. -hydroxy acids), poly (. beta. -hydroxyalkanoates), poly (. omega. -hydroxyalkanoates), and polyalkylene dicarboxylates and the like are preferred. In particular, polyglycolic acid, polylactic acid, poly (. beta. -hydroxybutyric acid), poly (. beta. -hydroxyvaleric acid), poly (. beta. -propiolactone), poly (. epsilon. -caprolactone, polyethylene succinate, polybutylene succinate, polyethylene oxalate, polybutylene oxalate and the like are preferable. First, polylactic acid and polyoxalate are most preferred.
Polylactic acid is hydrolyzed to produce lactic acid, which is particularly useful as a nutrient source and hydrogen donor for microorganisms. The polyoxalate represented by polyethylene oxalate or polybutylene oxalate is a polymer obtained by polycondensing oxalic acid with a diol such as ethylene glycol or butanediol, and has an extremely high hydrolysis rate as compared with polylactic acid.
Therefore, depending on the nature of the soil in which contaminated groundwater is present, the degree of contamination, the kind of contaminant, and the like, polylactic acid or polyoxalate may be selected for use as the hydrolyzable polymer, so that the respective properties of these polymers can be optimized.
In addition, in the case of using polylactic acid and polyoxalate in combination, an anaerobic environment can be formed by hydrolysis of polyoxalate in an early stage. Thereafter, when most of the polyoxalate is hydrolyzed, the hydrolysis of the polylactic acid may then form an anaerobic environment. As a result, an anaerobic environment can be stably formed for a long period of time. In addition, when used in combination with a polyoxalate, polylactic acid has a higher hydrolysis rate because the polyoxalate is hydrolyzed to generate an acid (oxalic acid) that accelerates the hydrolysis of polylactic acid.
In view of the above, it is preferable to use polylactic acid and polyoxalate in combination in the present invention. For example, the polyoxalate is most suitably used in an amount of 1 to 30 parts by mass relative to 100 parts by mass of the polylactic acid.
In the present invention, the hydrolyzable polymer is preferably used in the form of a particulate substance. For example, the volume-based average particle diameter D of the particulate matter measured by a laser diffraction scattering method50Preferably in the range of 1 to 100. mu.m. When injected into soil, hydrolyzable polymer particles having an appropriate particle size tend to stay at the same position because even if groundwater flows rapidly, it is less likely to be carried and easily penetrates into gaps between soil particles in the ground. As a result, the hydrolyzable polymer particles gradually hydrolyze in situ, contributing to the formation of an anaerobic environment. Further, even if groundwater contains oxygen, nitrate ions, sulfate ions and the like, their influence on the particle surface such as reduced hydrolyzability and the like caused by oxidation and the like is limited, and the interior of the particle can be effectively prevented from such adverse influence.
The particulate matter of such a hydrolyzable polymer may be obtained by producing a hydrolyzable polymer, for example, by emulsion polymerization or suspension polymerization, or alternatively, by subjecting hydrolyzable resin pellets obtained by melt extrusion to mechanical pulverization, followed by appropriate sieving, or the like.
The weight average molecular weight (Mw) of the hydrolyzable polymer used in the present invention is preferably 12,000 or more, particularly 20,000 or more. When the weight average molecular weight is too low, the hydrolyzable polymer is completely hydrolyzed and disappears in a short time, which is disadvantageous for maintaining an anaerobic environment for a long time. In addition, such a low weight average molecular weight hydrolyzable polymer tends to be disadvantageous from the viewpoint of granulation by mechanical pulverization.
The weight average molecular weight (Mw) was measured by GPC with polystyrene as a standard substance.
Water-soluble organic solvent:
the water-soluble organic solvent used in the present invention is itself a hydrogen donor, which serves as a nutrient source for aerobic and anaerobic microorganisms to contribute to the formation of an anaerobic environment. Therefore, the organic solvent needs to be, for example, a nonvolatile liquid having a boiling point higher than 100 ℃. In the case of volatile liquids such as methanol or ethanol, they are readily volatilized without contributing to the formation of an anaerobic environment. In addition, such volatile liquids are not suitable for long-term storage in the form of a dispersion before injection into the soil, since the organic solvent evaporates from the system.
In addition, the organic solvent of the present invention has high affinity for the hydrolyzable polymer so that the hydrolyzable polymer particles are uniformly dispersed and are soluble in water to easily penetrate into the ground in the ground. In the case of a water-insoluble organic solvent in which, for example, the solubility in water is 1g/100mL or less, it is less likely to penetrate into the ground and therefore does not contribute to the formation of an anaerobic environment.
Further, the water-soluble organic solvent of the present invention is required to be capable of keeping the water content of the polymer dispersion at 30% by mass or less, preferably 10% by mass or less and more preferably 1% by mass or less. The hydrolysis of the hydrolyzable polymer dispersed in the organic solvent proceeds as the water content is higher. As a result, most of the hydrolyzable polymer has hydrolyzed and disappeared before being injected into the ground. For the same reason, even if the water content can be kept in a suitable range, it is not possible to use a lower primary alcohol such as ethanol or methanol or an anhydride thereof as the solvent of the present invention, because such an alcohol itself is likely to hydrolyze the hydrolyzable polymer.
In the present invention, a water-soluble organic solvent is mixed with the hydrolyzable polymer particles so that the hydrolyzable polymer in the form of a particulate substance is dispersed. The viscosity (50 ℃) of the dispersion thus obtained is required to be such that the drop time measured by a Zahn cup having an opening diameter of 5mm or less is 180 seconds or less, particularly 120 seconds or less. When the viscosity is too high, the dispersion adheres to the wall of the mixing tank in a large amount and is difficult to take out from the mixing tank. As a result, it becomes difficult to obtain a large-capacity dispersion.
In view of the above, representative examples of the water-soluble organic solvent used in the present invention include polyhydric alcohols such as ethylene glycol, propylene glycol, 1, 4-butanediol, and triethylene glycol, although the present invention is not limited thereto. The alcohol is suitably selected from these alcohols in view of, for example, affinity for the hydrolyzable polymer to be used. A variety of alcohols can be selected to produce a mixed solvent.
For example, when a carboxylic acid salt such as sodium lactate is mixed with a hydrolyzable polymer, the resulting mixture becomes significantly viscous, which makes it impossible to prepare a large-volume dispersion using a mixing kettle. In order to reduce the viscosity, the mixture needs to be diluted with water, thus making it impossible to prevent the hydrolysis of the hydrolyzable polymer during storage or transportation.
High capacity organic solvent polymer dispersions:
in order to prepare the dispersion of the present invention formed of the hydrolyzable polymer and the water-soluble organic solvent as described above in a large capacity by uniformly mixing using a mixing tank, the hydrolyzable resin and the water-soluble organic solvent are used at such a quantitative ratio that the viscosity (50 ℃) of the dispersion is such that the drop time measured by a Zahn cup having an opening diameter of 5mm or less is 120 seconds or less. From the viewpoint of large-volume preparation, the dispersion preferably has a low viscosity. However, when the viscosity of the dispersion is lower than necessary, it contains an excessive amount of the organic solvent, which impairs the effect of the hydrolyzable polymer to maintain an anaerobic environment for a long period of time. Therefore, in the present invention, it is desirable to set the amount ratio between the hydrolyzable resin and the water-soluble organic solvent so that the hydrolyzable polymer and the organic solvent are contained in a well-balanced manner. The specific amount ratio cannot be specified altogether because it varies depending on the molecular weight and kind of the hydrolyzable polymer used and the kind of the water-soluble organic solvent. It is generally preferable to contain the non-hygroscopic water-soluble organic solvent in an amount of 50 parts by mass or more, particularly 100 parts by mass or more, relative to 100 parts by mass of the hydrolyzable polymer.
The capacity of the above large-capacity organic solvent polymer dispersion is 500L or more, preferably 1,000L or more, in view of industrial application. When the capacity is larger than this, it becomes difficult to take out the dispersion from the upper part of the mixing tank with a ladle or the like or by inverting the mixing tank itself. Therefore, it is particularly useful to control the viscosity in a low viscosity range.
Further, the large-capacity organic solvent polymer dispersion of the present invention is required to have a water content controlled to 30% by mass or less, preferably 10% by mass or less and more preferably 1% by mass or less to prevent hydrolysis of the hydrolyzable polymer before injection into the ground. For this reason, it is most suitable that the hydrophilic organic solvent is substantially anhydrous. However, the organic solvent may contain a certain amount of moisture due to its hydrophilicity as long as the water content of the dispersion is within the above range. Further, the dispersion may be exposed to the atmosphere as long as the water content is maintained within the above range.
Since the high-capacity organic solvent polymer dispersion of the present invention contains a limited amount of water as described above, hydrolysis of the hydrolyzable polymer is prevented. For example, the retention of the weight average molecular weight (Mw) of the hydrolyzable polymer when left at 50 ℃ for 30 days is 70% or more, particularly 80% or more.
Use of high capacity organic solvent polymer dispersions
The high capacity organic solvent polymer dispersions of the present invention described above are particularly useful for the purification of contaminated groundwater and for in situ injection into soil where contaminated groundwater is present.
The dispersion may be injected directly into the soil. Typically, however, the dispersion is diluted with water prior to injection. This allows the dispersion to be quickly injected into the ground. For example, the dispersions of the present invention are quickly and uniformly diluted with water without whipping.
In the present invention, there is no particular limitation on the contaminants contaminating the groundwater to be purified. However, the present invention is effectively applied to volatile organic chlorine compounds (VOCs), nitric nitrogen, nitrite nitrogen, and the like, which are managed according to environmental quality standards for groundwater pollution.
Here, VOCs are chemicals that are widely used for industrial purposes as solvents and detergents. Examples thereof include tetrachloroethylene, trichloroethylene, cis-1, 2-dichloroethylene, 1, 1-dichloroethylene, vinyl chloride, 1,1, 1-trichloroethane, 1,1, 2-trichloroethane, 1, 2-dichloroethane, tetrachloroethane, carbon tetrachloride, chloroform and dichloromethane.
Nitric and nitrous nitrogen are mainly derived from nitrogen fertilizers, livestock excreta and domestic sewage. Some of which are converted to nitrites and eventually nitrates by the action of microorganisms in the soil through ammonia nitrogen. Nitric acid-soluble nitrogen and nitrite-soluble nitrogen are readily dissolved in water and are not readily retained in soil, and thus, are readily dissolved in groundwater.
The polymer dispersion for purifying groundwater containing the above-mentioned contaminants can be injected into the ground by a method known per se such as the method disclosed in JP 2018-143918A (patent document 2).
The large-capacity polymer dispersion of the present invention is suitable not only for large-scale consumption by underground supply but also for the production of fracturing fluids and the like in the well drilling field because the hydrolyzable polymer exhibits moderate hydrolyzability.
Examples
The excellent effects of the present invention will be illustrated by the following experimental examples.
< raw materials >
< organic solvent >
Ethylene Glycol (EG):
ethylene glycol (guaranteed reagent) manufactured by FUJIFILM Wako Pure Chemical Corporation, (purity: at least 99.5% (w/w) or more)
Triethylene glycol (TEG):
triethylene glycol, manufactured by Tokyo Chemical Industry Co., Ltd. (purity: more than 99.0%)
Propylene Glycol (PG):
propylene glycol (guaranteed reagent) manufactured by FUJIFILM Wako Pure Chemical Corporation (purity: at least 99.0% (w/w) or more)
Methanol:
methanol, manufactured by FUJIFILM Wako Pure Chemical Corporation (methanol content: 99.7%, for high performance liquid chromatography)
50% aqueous lactic acid solution:
musashino lactic acid 50F, manufactured by Musashino Chemical Laboratory, Ltd
Sodium lactate (LaNa):
sodium L-lactate solution (about 70%), manufactured by FUJIFILM Wako Pure Chemical Corporation; 16.7g of pure water was added to 100g of the solution.
< hydrolyzable Polymer >
The hydrolyzable polymer used is a low molecular weight product obtained by melt kneading polylactic acid (PLA) and polyethylene oxalate (PEOx).
The PLA used was revolute 101 manufactured by Zheijiang Hisun Biomaterials co. When used as a feedstock, the molecular weight is in the range of 120,000< Mw <170,000.
The PEOx used is a product obtained by polymerization as will be described in the following section. The reduced viscosity was 0.84 dL/g. The production method thereof will be described below.
< Synthesis of PEOx >
40kg (339mol) of dimethyl oxalate, 23.2kg (374mol) of ethylene glycol, 2.9kg (32.2mol) of 1, 4-butanediol and 8.4g of dibutyltin oxide were introduced into a 150L reaction vessel which could be heated by a heating medium, and then, heated under a nitrogen stream so that the liquid temperature in the reaction vessel reached 110 ℃, followed by atmospheric polymerization.
After the start of the distillation of methanol, the liquid was kept warm for one and a half hours to allow the reaction to proceed. After one and a half hours has elapsed, the temperature of the liquid is raised to 130 ℃ at a ramp rate of 10 ℃/hour and further to 190 ℃ at a ramp rate of 20 ℃/hour. The amount of recovered liquid was 21.2 kg.
Thereafter, the liquid in the flask was subjected to polymerization under reduced pressure at a temperature of 190 ℃ and a reduced pressure of 0.1 to 0.8kPa, and the polymer thus obtained was extracted. The polymer was heat treated at 90 ℃ for 2 hours and at 120 ℃ for 2 hours.
< melt kneading of PLA and PEOx >
90 parts by mass of PLA as a raw material and 10 parts by mass of synthetic PEOx were metered by respective metering feeders to a continuous twin-screw extruder, followed by melt kneading. The temperature of the extruder was 200 ℃. The melt-kneaded resin was shaped into a spherical shape by an underwater cutter.
< reduction in molecular weight of hydrolyzable Polymer and grinding >
200kg of the above melt-kneaded resin and 200kg of 50% aqueous lactic acid solution were introduced into a 1,000L capacity reaction kettle which could be heated by a heating medium, and then stirred at 100 ℃ for 2 hours to react with each other. After the reaction, the product was cooled to room temperature, followed by separating the resin from the solution by a centrifuge. The separated resin was washed with water and then dried under vacuum at 70 to 90 ℃ by a conical dryer of 300L capacity, thereby obtaining a low molecular weight hydrolyzable polymer.
The resin thus obtained was mechanically pulverized to fine powder by a jet mill (D)50＝7μm)。
< various evaluation methods >
< measurement of reduced viscosity of PEOx >
Equipment: Cannon-Fenske type viscometer
Solvent: 1,1,1,2,2, 2-hexafluoro-2-propanol
Temperature: 25 deg.C
Sample preparation: 10mL of solvent was added to 40mg of sample and stirred slowly at room temperature. After the dissolution of the sample in the solvent was confirmed visually, the sample was filtered through a 0.45 μm filter to prepare a measurement sample.
< measurement of molecular weight of hydrolyzable Polymer >
The molecular weight of the hydrolyzable polymer was measured under the following conditions.
Equipment: high speed GPC apparatus HLC-8320, manufactured by Tosoh Corporation
A detector: differential refractometer RI
Column: SuperMultipore HZ-M (2 connected column)
Solvent: chloroform
Flow rate: 0.5mL/min
Column temperature: 40 deg.C
Sample preparation: 3mL of solvent was added to about 10mg of the powder sample. The sample was visually confirmed to be dissolved in the solvent and filtered through a 0.45 μm filter, thereby preparing a measurement sample. Polystyrene was used as a standard.
< measurement of molecular weight holding ratio >
About 10g of the hydrolyzable polymer dispersion prepared in each example was put into a glass vial container of 20mL capacity, which was then closed with a PP stopper and left to stand in an oven set at 50 ℃. After 30 days, 2mL of the dispersion was extracted and centrifuged at 10,000rpm for 2 minutes, thereby separating the fine powder from the solvent. The fine powder was subjected to centrifugal separation with pure water in the same manner to wash, and then vacuum-dried at 40 ℃ for 4 hours, thereby obtaining a powder sample. The powder sample thus obtained was subjected to GPC measurement to evaluate the molecular weight.
Molecular weight retention ratio XkeepThe molecular weight obtained by GPC measurement was used and calculated by the following formula (1).
Xkeep＝MWfinish/MWinitial
Xkeep: molecular weight retention
MWfinish: weight average molecular weight of the hydrolyzable Polymer after standing at 50 ℃ for 30 days
MWinitial: weight average molecular weight of the just-prepared hydrolyzable Polymer
< measurement of Water content >
The water content W of the organic solvent polymer dispersion was calculated from the following formula (2) by using the water contents of the organic solvent and the powder measured separately.
W＝Xsolvent×Wsolvent+Xpowder×Wpowder···(2)
W: water content of organic solvent Polymer Dispersion (%)
Xsolvent: mass fraction of solvent in organic solvent polymer dispersion
Wsolvent: water content of solvent (%)
Xpowder: mass fraction of powder in organic solvent polymer dispersion
Wpowder: moisture content of powder (%)
The water content of the solvent was measured under the following conditions, and the water content of the hydrolyzable polymer was measured.
Equipment: moisture meter (volumetric titration method) KF-31 manufactured by Mitsubishi Chemical Analyticch, Co., Ltd
Titration solvent: AQUAMICRON SS-Z3 mg
Sample preparation: measurements were made immediately after unsealing of the commercially available reagents.
The water content of the powder was measured by using the following apparatus, and the water content of the hydrolyzable polymer was measured.
Equipment: micro-moisture meter CA-200, manufactured by Mitsubishi Chemical Analytech, Co., Ltd
< measurement of viscosity >
Equipment: zahn cup #4 (opening diameter: 4.4mm), manufactured by BEVS Industrial Co., Ltd
Sample preparation: the prepared hydrolyzable polymer dispersion was placed in a room at 50 ℃ overnight, and then the falling time was measured in the same room by using a Zahn cup.
The measuring method comprises the following steps: the Zahn cup was immersed in the hydrolyzable polymer dispersion and then lifted to a height of about 5cm from the liquid surface at the bottom. The time from lifting the Zahn cup until the entire hydrolyzable polymer dispersion in the Zahn cup falls and the liquid flowing out from the bottom is interrupted was measured as an evaluation value.
The evaluation method comprises the following steps: when the evaluation value of this measurement is less than 120 seconds, the hydrolyzable polymer dispersion can be appropriately taken out through the discharge pipe even when produced by a large-capacity tank.
(example 1)
100g of the hydrolyzable polymer and 200g of EG were put into a 600 mL-capacity plastic cup container, followed by stirring at 20,000rpm for 3 minutes by a high-speed stirrer (HSIANGTAI ST-200, manufactured by AS ONE Corporation), thereby obtaining a hydrolyzable polymer dispersion.
(example 2)
A hydrolyzable polymer dispersion was obtained in the same manner as in example 1, except that TEG was used instead of EG.
(example 3)
A hydrolyzable polymer dispersion was obtained in the same manner as in example 1, except that PG was used instead of EG.
(example 4)
A hydrolyzable polymer dispersion was obtained by placing 30g of a hydrolyzable polymer and 300g of PG in a plastic cup container having a capacity of 600mL and then treating the mixture in the same manner as in example 1.
Comparative example 1
A hydrolyzable polymer dispersion was obtained in the same manner as in example 1, except that water was used instead of EG.
Comparative example 2
A hydrolyzable polymer dispersion was obtained in the same manner as in example 1, except that methanol was used instead of EG.
Comparative example 3
A hydrolyzable polymer dispersion was obtained in the same manner as in example 1, except that LaNa was used instead of EG.
< physical Properties of hydrolyzable Polymer Dispersion >
Measuring physical properties of each of the hydrolyzable polymer dispersions prepared as described above; the results are shown in table 1.
In examples 1 to 4, the falling time at 50 ℃ measured by a Zahn cup was suitable, and the molecular weight retention was as high as 80% or more. This demonstrates that the polymer dispersion obtained in the present invention is easy to take out from a pot and package even when prepared in a large capacity, and can effectively prevent deterioration of a hydrolyzable polymer even when stored for a long period of time.
[ Table 1]
Claims (8)
1. A large-capacity organic solvent polymer dispersion in which a hydrolyzable polymer is dispersed in a nonvolatile water-soluble organic solvent, the dispersion maintaining a water content of 30 mass% or less and a drop time at 50 ℃ measured by a Zahn cup having an opening diameter of 5mm or less of 180 seconds or less.
2. The high capacity organic solvent polymer dispersion according to claim 1, which has a capacity of 1,000L or more.
3. The high capacity organic solvent polymer dispersion according to claim 1, wherein the water-soluble organic solvent is a polyol.
4. The high capacity organic solvent polymer dispersion according to claim 1, wherein the hydrolyzable polymer is an aliphatic polyester.
5. The high capacity organic solvent polymer dispersion according to claim 4, wherein the aliphatic polyester is polylactic acid or polyoxalate.
6. The high capacity organic solvent polymer dispersion according to claim 1, wherein the retention of the weight average molecular weight of the hydrolyzable polymer when left at 50 ℃ for 30 days is maintained at 80% or more.
7. A method of using a large capacity organic solvent polymer dispersion, comprising supplying the large capacity organic solvent polymer dispersion of claim 1 into the ground.
8. The method of claim 7, wherein the high capacity organic solvent polymer dispersion is injected into soil to purify contaminated groundwater.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2019092708A JP7415333B2 (en) | 2019-05-16 | 2019-05-16 | Organic solvent dispersion of hydrolyzable resin |
| JP2019-092708 | 2019-05-16 | ||
| PCT/JP2020/006723 WO2020230395A1 (en) | 2019-05-16 | 2020-02-20 | Organic-solvent dispersion of hydrolyzable polymer |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN113825571A true CN113825571A (en) | 2021-12-21 |
Family
ID=73220861
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202080036301.3A Pending CN113825571A (en) | 2019-05-16 | 2020-02-20 | Organic solvent dispersions of hydrolyzable polymers |
Country Status (5)
| Country | Link |
|---|---|
| US (1) | US20220213316A1 (en) |
| EP (1) | EP3970871A4 (en) |
| JP (1) | JP7415333B2 (en) |
| CN (1) | CN113825571A (en) |
| WO (1) | WO2020230395A1 (en) |
Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005081158A (en) * | 2003-09-04 | 2005-03-31 | Matsushita Electric Ind Co Ltd | Soil/ground water cleaning composition |
| CN102398985A (en) * | 2010-09-17 | 2012-04-04 | 同和环保再生事业有限公司 | Organic halide decomposer, process for producing the same, and method for purifying soil or water |
| JP2017042737A (en) * | 2015-08-28 | 2017-03-02 | 大成建設株式会社 | Contaminated groundwater cleanup method |
| CN107207978A (en) * | 2015-02-27 | 2017-09-26 | 陶氏环球技术有限责任公司 | The stable aqueous pour point depressant dispersion composite of varsol |
| WO2018159741A1 (en) * | 2017-03-01 | 2018-09-07 | 大成建設株式会社 | Method for purifying contaminated groundwater |
| JP2019062808A (en) * | 2017-09-29 | 2019-04-25 | 東洋製罐グループホールディングス株式会社 | Production method of nutrient solution for microorganisms |
Family Cites Families (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3386279B2 (en) * | 1995-03-09 | 2003-03-17 | 積水化成品工業株式会社 | Resin mixture and method for producing the same |
| JP3694294B2 (en) * | 2003-01-10 | 2005-09-14 | 株式会社竹中工務店 | In-situ purification method for contaminated soil and / or groundwater |
| JP2006218456A (en) * | 2005-02-14 | 2006-08-24 | Kokusai Kogyo Co Ltd | Soil purifying method utilizing biodegradable resin |
| JP4079976B2 (en) * | 2006-08-25 | 2008-04-23 | エコサイクル株式会社 | Purification agent and organic chlorine compound purification method using the purification agent |
| US8501445B2 (en) * | 2008-10-27 | 2013-08-06 | Toyo Seikan Kaisha, Ltd. | Method for producing oligomer and/or monomer by degrading biodegradable resin |
| CN104854215B (en) * | 2012-12-12 | 2018-03-13 | 东洋制罐集团控股株式会社 | Excavation dispersion liquid and the method using dispersion liquid digging subterranean resource |
| JP6183039B2 (en) * | 2012-12-12 | 2017-08-23 | 東洋製罐株式会社 | Dispersion liquid for excavation and mining method using the same |
| JP6264960B2 (en) * | 2014-03-11 | 2018-01-24 | 東洋製罐グループホールディングス株式会社 | Polylactic acid composition |
| JP6451061B2 (en) * | 2014-03-11 | 2019-01-16 | 東洋製罐グループホールディングス株式会社 | Submerged resin molding |
| JP6492611B2 (en) * | 2014-12-15 | 2019-04-03 | 東洋製罐グループホールディングス株式会社 | Polyoxalate copolymer |
-
2019
- 2019-05-16 JP JP2019092708A patent/JP7415333B2/en active Active
-
2020
- 2020-02-20 WO PCT/JP2020/006723 patent/WO2020230395A1/en active Application Filing
- 2020-02-20 CN CN202080036301.3A patent/CN113825571A/en active Pending
- 2020-02-20 US US17/609,663 patent/US20220213316A1/en active Pending
- 2020-02-20 EP EP20805873.5A patent/EP3970871A4/en active Pending
Patent Citations (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005081158A (en) * | 2003-09-04 | 2005-03-31 | Matsushita Electric Ind Co Ltd | Soil/ground water cleaning composition |
| CN102398985A (en) * | 2010-09-17 | 2012-04-04 | 同和环保再生事业有限公司 | Organic halide decomposer, process for producing the same, and method for purifying soil or water |
| CN107207978A (en) * | 2015-02-27 | 2017-09-26 | 陶氏环球技术有限责任公司 | The stable aqueous pour point depressant dispersion composite of varsol |
| JP2017042737A (en) * | 2015-08-28 | 2017-03-02 | 大成建設株式会社 | Contaminated groundwater cleanup method |
| WO2018159741A1 (en) * | 2017-03-01 | 2018-09-07 | 大成建設株式会社 | Method for purifying contaminated groundwater |
| JP2019062808A (en) * | 2017-09-29 | 2019-04-25 | 東洋製罐グループホールディングス株式会社 | Production method of nutrient solution for microorganisms |
Also Published As
| Publication number | Publication date |
|---|---|
| EP3970871A4 (en) | 2023-01-25 |
| JP2020186329A (en) | 2020-11-19 |
| US20220213316A1 (en) | 2022-07-07 |
| WO2020230395A1 (en) | 2020-11-19 |
| EP3970871A1 (en) | 2022-03-23 |
| JP7415333B2 (en) | 2024-01-17 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| EP1970399B1 (en) | Process for producing polyglycolic acid resin composition | |
| US9156942B2 (en) | Method and device for cleaning an absorptive polyester | |
| CN110291146B (en) | Decomposition of polycondensates | |
| JP3510398B2 (en) | Method for producing hydroxycarboxylic acid-based polyester composition | |
| JP5224815B2 (en) | Polyglycolic acid resin granular composition and method for producing the same | |
| EP2933305B1 (en) | Fluid dispersion for drilling, and mining method using same | |
| WO2012121294A1 (en) | Polyglycolic acid resin particulate composition for boring, and method for producing same | |
| EP2933306B1 (en) | Use of fluid dispersion for drilling, and mining method for underground resources using said fluid | |
| EP3258058A1 (en) | Method for mining underground resources using hydrolyzable particles | |
| Simão et al. | Thermal properties and crystallinity of PCL/PBSA/cellulose nanocrystals grafted with PCL chains | |
| WO2015037605A1 (en) | Biodegradable resin composition having a porous structure and method for surface treatment of same | |
| CN113825571A (en) | Organic solvent dispersions of hydrolyzable polymers | |
| US20130131209A1 (en) | Polyglycolic Acid Particle, Production Process of Polyglycolic Acid Particle, and Use Thereof | |
| JP6911684B2 (en) | Manufacturing method of nutrient solution for microorganisms | |
| JP2017042737A (en) | Contaminated groundwater cleanup method | |
| JP2019065159A (en) | Method for reducing molecular weight of polymer component consisting of aliphatic polyester | |
| JP6906330B2 (en) | How to purify contaminated groundwater | |
| ES2302910T3 (en) | CONTINUOUS PRODUCTION PROCEDURE OF A POLYMER BASED POLYMER. | |
| CN112399979B (en) | Polylactic acid copolymer and method for producing same | |
| EP3150659A1 (en) | Method for decomposing ester resin | |
| WO2012012064A1 (en) | Processes for producing thermostable polyhydroxyalkanoate and products produced therefrom | |
| TW200302237A (en) | Method for treating polyester polymers and polyester polymers with low content of low-boiling components | |
| EP3950839B1 (en) | Solid poly(lactic acid) composition and production method therefor | |
| JP5033396B2 (en) | Polylactic acid composition | |
| MXPA04009452A (en) | Compounds useful for reducing acetaldehyde content of polyethylene terephthalate, their use and products resulting therefrom. |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |